Froth flotation is used for beneficiating ores. In particular, froth flotation can be used for separating valuable minerals in an ore from their associated gangue, or for separating the valuable minerals from one another. Froth flotation involves mixing an aqueous slurry containing finely ground ore particles with a frothing or foaming agent to produce a froth. Ideally, ore particles that contain the desired mineral are preferentially attracted to the froth because of an affinity between the froth and the exposed mineral on the surfaces of the ore particles. The resulting beneficiated minerals are then collected by separating them from the froth.
The ability of a mineral to float is related to its surface properties. Chemical reagents known as “collectors” are used to modify surface properties of minerals, and may be added to the slurry to increase the selectivity and efficiency of the separation process.
Because of the large scale on which mining operations are typically conducted and the large difference in value between the desired mineral and the associated gangue, even relatively small increases in separation efficiency provide substantial gains in productivity.